Housing for rotary mechanisms



Oct. 6, 1964 Filed June 28, 1961 FIG-2- W. G. FROEDE ETAL HOUSING FOR ROTARY MECHANISMS 2 Sheets-Sheet 1 INVENTORS WALTER G. EROEDE ERNST HOPPNER HANNS-DIETER PASCHKE BY //gr M F 7M, 24/2644 V ATTORNEYS Oct. 6, 1964 w. G. FROEDE E'TAL 3,151,307

HOUSING FOR ROTARY MECHANISMS Filed June 28, 1961 2 Sheets-Sheet 2 FIG-3.

FIG.5.

INVHVTORS WALTER c. EROEDE ERNST HOPPNER HANNS-DIETER PASCHKE y fmymz, par/m ATTORNEYS United States Patent 3,151,807 HOUSlNG FOR ROTARY MECHANISMS Walter G. Froede, Neckarsulm, Ernst Hiippner, Lindau (Bodensee), and Hanns-Dieter Paschlre, Neck-arsulm,

Germany, assignors to NSU Motorenwerke Alrtiengesellsehaft, Neckarsulm, and Wankel G.m.b.I-I., Lindau (Bodensee), Germany Filed June 28, 1961, Ser. No. 120,367 Claims priority, application Germany June 30, 1960 3 Claims. (Cl. 230-145) This invention relates to housings for rotary mechanisms and more particularly to housing means for rotary combustion engines that will permit these housings to be manufactured with cooling passages or cavities of complicated shapes by providing a means for the housing that will permit die-casting to be used.

Although this invention is applicable to and useful in almost any type of rotary mechanism that presents a cooling requirement, such as rotary combustion engines, fluid motors, fluid pumps, compressors, and the like, it is particularly useful in rotary combustion engines.

To simplify the explanation of the invention, the description that follows will, for the most part, be restricted to the use of the invention in a rotary combustion engine. It will be apparent from the description, however, that with slight modifications that would be obvious to a person skilled in the art, the invention is equally applicable to other types of rotary mechanisms.

The present invention is particularly useful in rotary combustion engines of the type that is described in detail in Patent No. 2,988,065 issued June 13, 1961, and reference may be made to the disclosure of this patent for a detailed description of such a rotary combustion engine.

This invention relates to a housing for such rotary combustion engines. These rotary combustion engines comprise an outer body having an axis, axially-spaced end walls, and a peripheral wall interconnecting the end walls. The inner surface of the peripheral wall and the end walls form a cavity, and the engine also includes a rotor that is mounted within the cavity between its end walls.

The axis of the rotor is eccentric from and parallel to the axis of the cavity of the outer body. The rotor has axially-spaced end faces disposed adjacent to the end walls of the outer body and a plurality of circumferentiallyspaced apex portions. The rotor is rotatable relative to the outer body, and its apex portions substantially continuously engage the inner surface of the outer body to form a plurality of working chambers that vary in volume during engine operation, as a result of relative rotation between the rotor and outer body.

To cool the outer body or housing of a rotary combustion engine, it has been previously known to provide the end walls, as well as the peripheral wall, with cavities or passages for the flow of a cooling liquid or gaseous cooling medium. The manufacture of the parts of the outer body having such cavities or passages has required the use of casting cores of complicated shapes. Also, because of the use of enclosed passages and cavities, manufacture of the housing by a die-casting process has not heretofore been possible.

It is a primary object of this invention to provide means for creating the housing or outer body of a rotary combustion engine that will permit the housing to be constructed with fairly complex cooling cavities or passages by the method of die-casting or through normal casting methods but with the use of cores that can be easily retracted away from the cast piece. Manufacture of suitable housings is thus greatly facilitated and made more efiicient and less expensive.

It is another object of this invention to provide a housing or outer body for a rotary mechanism in which 3,151,807 Patented Oct. 6, 1964 ice the main parts forming the internal cavity of the outer body are cast but are then covered by a mantle that may be in two parts. It is also an object, however, to provide means by which the plane of partition at which the two parts of the mantle are joined is parallel but laterally displaced from the mid-portion of the peripheral wall of the outer body to avoid having parts that are connected to the peripheral wall, for example, the intake and exhaust passages and the spark plug, from being disposed in the plane of partition or line of juncture of the two parts of the mantle.

Another object of this invention is to provide means by which the mantle for the housing may be made of drawn sheet metal to make the rotary mechanism as small and light as possible. These sheet metal parts may be undetachably connected with each other, for example, by beading the adjacent edges together. The outer diameter of the mantle may thus be made as small as possible because no connecting flanges with expensive screw-connections are required. Finally, this construction provides the advantage that the rotary mechanism or engine can then be open only in special or authorized repair shops so that unauthorized alterations of the engine may be prevented.

It is another object of this invention to provide means so that one part of the mantle may be formed from a dish-shaped metal part, while the other part may be formed as a rigid casting or forging that can also be used as a connecting flange for the mechanism.

Usually the housing is formed by connecting the end walls to the peripheral wall by means of screws. A screw connection has the disadvantage that in the region of the screws the passages for the cooling medium within the housing cannot be located as close to the inner surface of the peripheral wall as may be desirable, because of the space taken up by the screws.

It is, accordingly, an object of this invention to provide means by which the housing may be formed through a different connection of its parts by using the two parts of the mantle to clamp the end walls and the peripheral wall together so that the connection means joins the two parts of the mantle and does not have to pass through the end walls and the peripheral wall. This invention thus permits the thickness of the peripheral wall beneath the fins that forms the cooling passages to be kept very small so that heat transfer from the walls of the housing to the cooling medium is considerably improved.

The small wall thickness, however, if not properly combined with the configuration of the fins forming the cooling passages could have a deleterious effect by permitting the inner surface of the peripheral wall to become distorted in an undulating manner under the influence of thermal distortions and gas pressures. Since this inner surface serves as a sliding surface for engagement of the apex seals of the rotor, distortion of this surface can be a serious drawback. To avoid the undesirable effect just described on the apex seals, the cooling fins on the outer surface of the peripheral wall are arranged in a radial direction with respect to the outer body axis. By combining the cooling fins with a thin wall thickness in this manner, the inner surface of the peripheral wall that provides the sliding surface for the apex seals can be distorted only in a manner that would create slight radial grooves, and these would not cause a radial movement of the seals or cause them to jump away from the sliding surface.

It is a still further object of this invention to provide the mantle covering the cooling fins with two separate walls so that the outer cavity formed by the two walls of the mantle can be used as an oil cooler in engines having a separate lubricating circuit.

To achieve the foregoing objects, and in accordance carry the cooling passages and fins.

Additional objects and advantages of the invention will be set forth in part in the description that follows and in part will be obvious from the description, or may be learned by practice of the invention, the objects and advantages being realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

The invention consists in the novel parts, constructions, arrangements, combinations, and improvements shown and described.

The accompanying drawings that are incorporated in and constitute a part of this specification illustrate one embodiment of the invention and together with the description serve to explain the principles of the invention.

Of the drawings:

FIG. 1 is a central vertical section taken along the line 1 -1 of FIG. 2 of a rotary combustion engine comprising a present preferred embodiment of this invention;

FIG. 2 is a sectional view taken along the line 2-2 of FIG. 1;

FIG. 3 is a diagrammatic sectional View of a second embodiment of the present invention;

FIG. 4 is a diagrammatic sectional view of a third embodiment of this inventon; and

FIG. 5 is a diagrammatic sectional view of a fourth embodiment of the present invention.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory but are not restrictive of the invention.

Reference will now be made in detail to the present preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings.

In accordance with the invention, a rotary combustion engine and a novel means for forming the housing of such an engine are provided. As embodied, and as shown in FIGS. 1 and 2, the present preferred embodiment of 'the invention includes a rotary combustion engine comprising a generally triangular rotor having arcuate sides that is eccentrically supported for rotation within an outer body 12.

Although in the illustrative embodiment shown in the drawings the outer body 12 is fixed or stationary, a practical and useful form of the invention may be constructed in which both the outer body and rotor are rotary; in the latter form of the invention, the power shaft is driven directly by rotation of the outer body and the inner body or rotor rotates relative to the outer body.

As shown in FIGS. 1 and 2, and as here preferably embodied, the rotor 10 rotates on an axis 14 that is eccentric from and parallel to the axis 16 of the curved inner surface 18 of the outer body 12. The distance between the axes 14 and 16 is equal to the effective eccentricity of the engine. The curved inner surface 18 of the outer body 12 has basically the form of an epitrochoid in geometric shape and includes two arched lobedefining portions or lobes. As embodied, the generally triangular shape of the rotor 10 corresponds in its configuration to the inner envelope or the maximum profile of the rotor that will permit interference-free rotation of the rotor 10 Within the outer body 12.

In the form of the invention illustrated, the outer body 12 comprises a peripheral Wall 20 that has for its inner surface the curved inner surface 18, and a pair of axially- 4 spaced end walls 22 and 24 that are disposed on opposite sides of the peripheral wall 20.

The end walls 22 and 24-support a shaft 26, the geometric center of which is coincident with the axis 16 of the outer body 12. This shaft 26 is supported for rotation by the end walls 22 and 24 on bearings 28. A shaft eccentric 30 is rigidly attached to or forms an integral part of the shaft 26, and the rotor 10 is supported for rotation or rotatably mounted on the shaft eccentric 30 by a rotor bearing 32.

As shown in FIGS. 1 and 2 an internally-toothed or ring gear 34 is rigidly attached to one end face of the rotor 10. The ring gear 34 is in mesh with an externally-toothed gear or pinion 36 that is rigidly attached 'to the stationary end wall 24 of the outer body 12.

From this construction, it may be observed that the gearing 34 and 36 does not drive or impart torque'to the shaft 26 but serves to index or register the position of the rotor 10 with respect to the outer body 12 and to keep the rotor in phase as the rotor rotates relative to the outer body. The gearing also enforces the desired speed ratio between the rotor and the shaft and removes the positioning load that would otherwise be placed upon the apex portions of the rotor 10.

As shown most clearly in FIG. 2, the rotor 10 includes three apex portions 38 that carry radially movable sealing members 40. The sealing members 40 are in substantially continuous gas-sealing engagement with the inner surface 18 of the outer body 12 as the rotor 10 rotates Within and relative to the outer body 12.

By means of the rotation of the rotor 10 relative to the outer body 12, three variable volume working chambers 42 are formed'between the peripheral Working faces 44 of the rotor 10 and the inner surface 18 of the outer body As embodied in FIG. 2, the rotation of the rotor relative to the outer body is counterclockwise and is so indicated by an arrow.

A spark plug 46 is mounted in the peripheral Wall 20 of the outer body 12, and at the appropriate time in the engine cycle, the spark plug 46 provides ignition for a compressed combustible mixture which, on expansion, drives the rotor in the direction of the arrow. The rotary combustion engine may also be operated as a diesel, and when it is operated as a diesel, the spark plug 46 is not required, since ignition of the fuel is initiated by the temperature reached through high compression of the Working air.

Also as shown in FIG. 2, one lobe of the epitrochoidal surface 18 is provided with an intake port 48, and the other lobe is provided with an exhaust port 50. As the rotor 10 rotates, a fresh charge is drawn into the appropriate chamber 42 through the intake port 43. This charge is then successively compressed, ignited, expanded, and finally exhausted through the exhaust port 50.

All four successive phases of the engine cycle: intake, compression, expansion, and exhaust, take place Within each one of the variable volume Working chambers 42 each time the rotor 10 completes one revolution within the outer body, and for each revolution of the rotor, the engine completes a cycle.

The working faces 44 of the rotor 10 are provided with cut-out portions or channels 52 that permit combustion gases to pass freely from one lobe of the epitrochoidal inner surface 18 to the other lobe, when the rotor is at or near the dead center of maximum compression position. Also, a desired compression ratio for the engine may be attained by appropriate proportioning of the Volume of the channels 52.

In the present preferred embodiment the gear ratio .between the gearing 34 and 36 is 3:2 so that each time provided for forming the housing or outer body of the engine. As here preferably embodied, as shown in FIG. 1, the end walls 22 and 24 are provided at their outer surfaces 54 and 56 with radially extending fins 53 and 60. Similarly, the outer surface of the peripheral wall 20 is provided with radially and peripherally extending fins 62.

The end wall fins 60 are covered by a cover plate 64 that is connected to the end wall 24 by screws 66. The cover plate 64 instead of being of thin sheet metal may, as illustrated, be a relatively heavy and strong part, such as a casting or forging, whereby it can serve as a mounting flange for the engine. The screw 66 may perform a double function by additionally connecting the end wall 24 to the peripheral wall 20.

Also as shown in FIG. 1, the fins 58 and 62 of the end wall 22 and peripheral wall 20 are covered by a dishshaped sheet metal casing or mantle 68 that is connected to the end wall 22 by screws 70, and that is sealed against the end Wall cover plate 64 and against the bearing extension 72 of end wall 22 by means of rubber sealing rings 74 and 76, respectively.

By joining the cover plate 64 and the mantle 68 covering the fins 58, 60, and 62 a substantially closed series of channels or passages for the cooling medium are formed. The cooling medium is supplied through the inlet 78 and divides into three parallel partial flows. One partial flow enters into direct contact with the fins 58 of the end wall 22. The residual flow enters the region of the fins 62 of the peripheral wall 20 through passages 80 at the periphery of end wall 22 and peripheral wall 20. This fiow is then divided into one partial flow that contacts the fins 62 and another partial flow that can stream through passages 82 at the outer periphery of peripheral wall 26 and its fins 62 and through the periphery of the end wall 24 to the outer surface 56 of end wall 24 and into contact with cooling fins 69. After passing through their respective channels the partial flows are collected, withdrawn from the outer body through outlet 81.

As described, the intake and exhaust ports 48 and 50 pass through the peripheral wall 20. These ports preferably are disposed in the mid-plane of the peripheral wall. The two parts 64 and 63 of the outer mantle or casing are joined together adjacent to one end of the peripheral wall. This structure avoids the complication of having the intake and exhaust ports in the plane of junction of the mantle parts 64 and 68.

In the other embodiments of this invention, shown in FIGS. 3 through 5, the same or similar parts are designated with the same numbers.

The second embodiment of this invention as shown in FIG. 3, provides a mantle covering the fins 58, 60 and 62 that is formed from two dish-shaped sheet metal parts 84 and 86 that are undetachably connected together by a bead 88 and sealed against the end walls 22 and 24 by sealing rings 90 and 92.

The embodiment of the invention shown in FIG. 4 is similar to that shown in FIG. 1. In FIG. 4 the mantle comprises the two parts 94 and 96, and these parts in addition to scaling to the cooling passages of the outer body perform the function of connecting the main parts of tthe outer body 12 comprising the two end walls 22 and 24 and the peripheral wall 20. The main parts of the housing, the end walls 22 and 24, and the peripheral wall 20, are clamped together by tightening of the screws 98 shown in FIG. 4.

In accordance with the invention, the means provided by the embodiment of FIG. 4 for clamping together the main parts of the housing eliminates the need for the screws that are otherwise necessary to fasten the end walls 22 and 24 to the peripheral wall 20. This embodiment of the invention thus permits, through elimination of the screws, the thickness of the peripheral wall 20 between its fins 62 to be kept very small, so that heat transfer and removal from the peripheral wall is appreciably improved in efficiency. The support of this relatively thin peripheral wall is effected by the use of relatively strong cooling fins 62 that extend in a radial and peripheral direction, as shown in FIG. 4. The flanged edge 100 of the part 94 of the, mantle is reinforced by a ring 102. Sealing rings for the two-part mantle disclosed in FIG. 4 are designated 104.

The form of this invention shown in the embodiment of FIG. 5 corresponds to that shown in FIG. 4 with the single difierence that the part 94 of the mantle is comprised of two walls 106 and 108. Wall 106 forms an internal mantle, or the main mantle and wall 108 forms an external mantle over wall 106 so that a cavity 110 is formed between the two walls 106 and 108. This cavity 110 can be effectively used as an oil cooler. To facilitate the latter function, cooling fins 112 are arranged at the side of the cavity adjacent to the cooling surface or on the wall 106.

The second part 114 of the basically two-part mantle is also made of sheet metal and the connection of the parts 106, 108 and 114 is effected by screws 116. As in the previous embodiment shown in FIG. 4, so also in the embodiment of FIG. 5, the main parts of the outer body, the end walls 22 and 24 and the peripheral wall 20 are clamped together by the parts 106 and 114 of the mantle. The oil cooling cavity 110 in FIG. 5 is for use with an engine having a separate lubrication circuit. The means for circulating the oil to and from the oil cooler are not shown because they would be conventional.

This invention in its broader aspects is not limited to the specific mechanisms shown and described, but also includes within the scope of the accompanying claims any departures made from such mechanisms that do not sacrifice its chief advantages.

What is claimed is:

1. In combination with a rotary mechanism for fluid motors, rotary fluid pumps, rotary combustion engines or the like, comprising an outer body having an axis, axiallyspaced end walls, a peripheral wall interconnecting the end walls, the end walls and the peripheral wall defining a multi-lobed cavity coaxial with the outer body, and a rotor mounted within the outer body and rotatable relative to the outer body, the rotor having a plurality of circumferentially-spaced apex portions in sealing engagement with the inner surface of the peripheral wall to form a plurality of working chambers between the rotor and the inner surface of the outer body that vary in volume upon relative rotation of the rotor within the outer body, the rotor having one more apex portion than the outer body cavity has lobes :and each apex portion bearing an axially extending and radially movable seal member in contact with said inner surface; the improvement of a housing for the mechanism comprising cooling fins on the outer surface of the peripheral wall and the outer surface of the end walls, a mantle having a first part and a second part connected together, the mantle covering the outer surfaces and fins of the peripheral wall and the end walls in contact with the outer edges of the fins so that closed passages for a cooling medium are formed between the inner surface of the mantle and the outer surfaces of the peripheral wall and the end Walls, the housing including an inlet for introduction of the cooling medium to the housing and an outlet for removal of the cooling medium from the housing, the juncture of the two parts of the mantle being laterally displaced from the median plane of the peripheral wall, and the cooling fins on the outer surface of the peripheral wall extending circumferentially around the peripheral wall to obviate the formation of striations on the inner surface parallel with the seal members and to minimize radial movement of the seal members.

2. The invention as defined in claim 1, in which both parts of the mantle are undetachably connected together.

3. The invention as defined in claim 1, in which both 7 8 parts of the mantle comprise dish-shaped sheet metal 1,851,193 Laraque Mar. 29, 1932 parts. 2,079,192 Upshaw May 4, 1937 2,847,157 Nilsson Aug. 12, 1958 References Cited In the file of th1s patent 2,876,943 Hockel Man 10 1959 UNITED STATES PATENTS 5 2,988,065 Wankel et a1 June 13, 1961 1,331,177 Bair Feb. 17, 1920 FOREIGN PATENTS 1,598,867 Lundehus P 1926 14 4 Switzerland Aug 5 1931 1,712,945 Thannhauser May 14, 1929 

1. IN COMBINATION WITH A ROTARY MECHANISM FOR FLUID MOTORS, ROTARY FLUID PUMPS, ROTARY COMBUSTION ENGINES OR THE LIKE, COMPRISING AN OUTER BODY HAVING AN AXIS AXIALLYSPACED END WALLS, A PERIPHERAL WALL INTERCONNECTING THE END WALLS, THE END WALLS AND THE PERIPHERAL WALL DEFINING A MULTI-LOBED CAVITY COAXIAL WITH THE OUTER BODY, AND A ROTOR MOUNTED WITHIN THE OUTER BODY, AND ROTATABLE RELATIVE TO THE OUTER BODY, THE ROTOR HAVING A PLURALITY OF CIRCUMFERENTIALLY-SPACED APEX PORTIONS IN SEALING ENGAGEMENT WITH THE INNER SURFACE OF THE PERIPHERAL WALL TO FORM A PLURALITY OF WORKING CHAMBERS BETWEEN THE ROTOR AND THE INNER SURFACE OF THE OUTER BODY THAT VARY IN VOLUME UPON RELATIVE ROTATION OF THE ROTOR WITHIN THE OUTER BODY, THE ROTOR HAVING ONE MORE APEX PORTION THAN THE OUTER BODY CAVITY HAS LOBES AND EACH APEX PORTION BEARING AN AXIALLY EXTENDING AND RADIALLY MOVABLE SEAL MEMBER IN CONTACT WITH SAID INNER SURFACE; THE IMPROVEMENT OF A HOUSING FOR THE MECHANISM COMPRISING COOLING FINS ON THE OUTER SURFACE OF THE PERIPHERAL WALL AND THE OUTER SURFACE OF THE END WALLS, A MANTLE HAVING A FIRST PART AND A SECOND PART CONNECTED TOGETHER, THE MANTLE COVERING THE OUTER SURFACES AND FINS OF THE PERIPHERAL WALL AND THE END WALLS IN CONTACT WITH THE OUTER EDGES OF THE FINS SO THAT CLOSED PASSAGES FOR A COOLING MEDIUM ARE FORMED BETWEEN THE INNER SURFACE OF THE MANTLE AND THE OUTER SURFACES OF THE PERIPHERAL WALL AND THE END WALLS, THE HOUSING INCLUDING AN INLET FOR INTRODUCTION OF THE COOLING MEDIUM TO THE HOUSING AND AN OUTLET FOR REMOVAL OF THE COOLING MEDIUM FROM THE HOUSING, THE JUNCTURE OF THE TWO PARTS OF THE MANTLE BEING LATERALLY DISPLACED FROM THE MEDIAN PLANE OF THE PERIPHERAL WALL, AND THE COOLING FINS ON THE OUTER SURFACE OF THE PERIPHERAL WALL EXTENDING CIRUMFERENTIALLY AROUND THE PERIPHERAL WALL TO OBVIATE THE FORMATION OF STRIATIONS ON THE INNER SURFACE PARALLEL WITH THE SEAL MEMBERS AND TO MINIMIZE RADIAL MOVEMENT OF THE SEAL MEMBERS. 